Phillips 32PFL3403D-27 power board issues

[lee.micah11@yahoo.com]

I am currently working on a Phillips tv (32PFL3403D-27) that had stopped working a while back. First it started shutting off from time to time or even turning itself on from time to time. Eventually, it wouldn't even turn on other than the power light being on. I pulled the power board (picture below) out and with it powered on I am getting no voltage (24 V or 12 V) at the outputs for the scalar or panel. I am getting the 5 V output, but that is it.

Tracing the schematic (attached below), I saw that the voltage for those pins comes off of the secondary of the larger transformer (T901). I am getting no voltage at the secondary, but I do have power on the primary side of that transformer. The top 3 pins of the transformer have 360 VAC between them and the ground side of the primary (bottom pin). I did find a bad capacitor (C932), but that capacitor was after the secondary of the transformer which is currently receiving no voltage, so I know that is not the issue, but maybe played a role when the tv first started acting up.

I am leaning towards the transformer being bad, but I wanted to get opinions on this. I'm really not sure what I'm supposed to have on the primary side and since it seems finding parts for this board isn't that easy, I want to make sure I'm not overlooking anything. Any thoughts?

[budm]

Re: Phillips 32PFL3403D-27 power board issues

What DCV do have between the two legs of the main filter cap, around 400VDC?
The switched 12V/24V runs on boosted VDC from the PFC circuit, it also needs PS-ON to turn on the 12V/24V section.
So you need to report the pin labels and Voltages of the connector on the power supply that goes to the main board when TV is OFF and when power switch is activated.
BTW, the negative leg of the main filter cap the circuit GND ref point for the primary side.

[lee.micah11@yahoo.com]

Re: Phillips 32PFL3403D-27 power board issues

Wow, I had overlooked that completely. So update to the problem. I plugged the power board back in and hooked everything up and now the tv will come on. It powers up and the screen comes on like normal, but if I change the volume or channel it powers off briefly and then powers back on...any ideas of where to go or look from here?

[lee.micah11@yahoo.com]

Re: Phillips 32PFL3403D-27 power board issues

budm...thanks for the pointer about having to have the other cards connected. I would have wasted a lot of time on that. I did find the issue and the tv works great now. It was a combination of the bad capacitor and a bad connection. As I wiggled components I found one that made it work properly when I wiggled it. Again, thanks for the help!

[budm]

Re: Phillips 32PFL3403D-27 power board issues

Can you please provide the pictures of what you found wrong so it will help others in the future? Thanks.

[lee.micah11@yahoo.com]

Re: Phillips 32PFL3403D-27 power board issues

Definitely. The picture of the location of the bad capacitor is above, but I will attach it again below here. It is the C932 location on the schematic. The top was quite bulged out on the old capacitor. The suspected loose connections were on the board shown in the second picture below with red circles around them. I also took off the switches and worked everything, so I'm not 100 % sure that a sticking switch wasn't involved as well. I should have checked the tv between steps to see which actually fixed it, but I didn't do that. I will next time, so I know for sure what the culprit was.

Note: I have the tv together, so I took a screenshot of the board from the manual and added the red circles.

[bwillaimspc]

Re: Phillips 32PFL3403D-27 power board issues

did you replace the capasiter i have the same tv wont do anyhting no lighs wont come on has the same blown capasiter